Hitherto, halogen-containing flame retardants have been widely used, which are made mainly of an organic halide (mainly bromide), in order to impart flame retardance to shaped bodies made of organic polymeric materials, such as plastic products or synthetic fibers. Halogen-containing flame retardants have an excellent flame retardant effect; however, the halogen gas generated by decomposition upon a shaping process may corrode the shaping and processing machine, or may produce an adverse effect onto physical properties of the shaped body itself. Thus, as an alternative thereto, so-called non-halogen type flame retardants of various types have been developed.
Magnesium hydroxide is a nonpoisonous inorganic substance, and contains no halogen and is friendly to the environment. Thus, this substance has been widely used as a typical non-halogen type flame retardant. Considering that magnesium hydroxide is an inorganic substance, a surfactant may be used together therewith to attain, for example, an improvement of this substance in dispersibility in organic polymeric materials (Patent Document 1), and magnesium hydroxide particles are surface-treated with a surfactant, and then the surface-treated particles may be used (Patent Document 2).